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ECE Oral Comprehensive Exam for Doctoral Candidacy By: Bentolhoda Jafary

When: Thursday, April 26, 2018
10:45 AM - 12:45 PM
Where: Science & Engineering Building, Lester W. Cory Conference Room: Room 213A
Cost: Free
Description: Topic: Reliability and Maintenance Modeling of Systems Subject to Positive and Negatively Correlated Component Failure

Location: Lester W. Cory Conference Room, Science & Engineering Building (SENG), Room 213A

ABSTRACT:
A primary goal of maintenance is to minimize the consequences of component and system failures such as minimize cost and maximize availability. Two subcategories of maintenance actions include: preventive maintenance (PM) at predetermined time intervals prior to failure and emergency repair (ER) upon failure, where the cost and downtime of emergency repair is significantly greater than preventive maintenance. Traditional methods to model system reliability assume that the failures of the components comprising a system are statistically independent in order to simplify analysis. However, hundreds of empirical case studies have illustrated that component failures are often correlated. The independence assumption simplifies calculations, but is dangerous for safety critical systems that must be maintained because correlated failures can lower the mean time to failure, thereby increasing the probability that emergency repair will be required.

Checkpointing is a technique to backup work at periodic intervals so that if computation fails it will not be necessary to restart from the beginning but will instead be able to restart from the latest checkpoint. Performing checkpointing operations requires time. Therefore, it is necessary to consider the tradeoff between the time to perform checkpointing operations and the time saved when computation restarts at a checkpoint.

This proposal presents two contributions: (i) a method with an explicit correlation parameter to characterize the impact of correlated component failures on the optimal preventive maintenance interval of a system with arbitrary structure and (ii) a method to model the impact of correlated failures on a system that performs checkpointing.

NOTE: All ECE Graduate Students are ENCOURAGED to attend.
All interested parties are invited to attend. Open to the public.

Advisor: Dr. Lance Fiondella

Committee Members: Dr. Hong Liu and Dr. Liudong Xing, Department of Electrical & Computer Engineering, UMass Dartmouth; Dr. Donghui Yan, Department of Mathematics, UMass Dartmouth; Dr. Mark White, NASA Jet Propulsion Laboratory

*For further information, please contact Dr. Lance Fiondella at 508.999.8596, or by via email at lfiondella@umassd.edu.
Topical Areas: General Public, University Community, College of Engineering, Electrical and Computer Engineering